6-(3,5-Dimethylbenzyl)-5-ethyl-1-[(2-phenylethoxy)methyl]pyrimidine-2,4(1H,3H)dione

In the title pyrimidine derivative, C24H28N2O3, the uracil unit is essentially planar with an r.m.s. deviation of 0.0054 (1) Å for the eight non-H atoms. The pyrimidine ring is tilted by a dihedral angle of 77.08 (7)° with respect to the aromatic ring of the 3,5-dimethylbenzyl substituent, whereas it is nearly parallel to the benzene ring of the phenethoxymethyl unit, with a dihedral angle of 8.17 (8)°. An intramolecular C—H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked by a pair of amide–uracil N—H⋯O hydrogen bonds into an inversion R 2 2(8) dimer. These dimers are stacked along the b axis through π–π interactions with a centroid–centroid distance of 3.9517 (8) Å. Weak C—H⋯π interactions are also present.

In the title pyrimidine derivative, C 24 H 28 N 2 O 3 , the uracil unit is essentially planar with an r.m.s. deviation of 0.0054 (1) Å for the eight non-H atoms. The pyrimidine ring is tilted by a dihedral angle of 77.08 (7) with respect to the aromatic ring of the 3,5-dimethylbenzyl substituent, whereas it is nearly parallel to the benzene ring of the phenethoxymethyl unit, with a dihedral angle of 8.17 (8) . An intramolecular C-HÁ Á ÁO hydrogen bond generates an S(6) ring motif. In the crystal, molecules are linked by a pair of amide-uracil N-HÁ Á ÁO hydrogen bonds into an inversion R 2 2 (8) dimer. These dimers are stacked along the b axis throughinteractions with a centroid-centroid distance of 3.9517 (8) Å . Weak C-HÁ Á Á interactions are also present.
The residue was extracted with ether (3 × 50 ml), the combined organic fractions were collected, dried (MgSO 4 ) and evaporated under reduced pressure. The residue was chromatographed on silica gel column with CHCl 3 to afford a white solid, which was recrystallized from ethanol to obtain the title compound as colorless crystals.

Refinement
The amide H atom was located in a difference map and refined isotropically. The remaining H atoms were placed in calculated positions with d(C-H) = 0.93 for aromatic, 0.97 for CH 2 and 0.96 Å for CH 3 atoms. The U iso (H) values were constrained to be 1.5U eq of the carrier atom for methyl H atoms and 1.2U eq for the remaining H atoms. A rotating group model was used for the methyl groups.

Figure 1
The structure of the title compound, showing 30% probability displacement ellipsoids and the atom-numbering scheme.
Only the non-aromatic benzyl H and amide H atoms were shown for clarify.  Extinction correction: SHELXTL (Sheldrick, 2008), Fc * =kFc[1+0.001xFc 2 λ 3 /sin(2θ)] -1/4 Extinction coefficient: 0.0158 (11) Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.